It was a key term in John Locke's empiricism - the mind is a tabula rasa, a blank slate, onto which ideas are inscribed by experience. It is a treasured dogma of empiricism, which I also think is completely mistaken, on account of there being inherent faculties in the human mind, such as the ability to enquire language (pace Noam Chomsky et al.)

Learn to do good, refrain from evil, purify the mind ~ this is the teaching of the Buddhas